Rehospitalization Does Not Mediate Link Between Delirium, Cognitive Decline

FRIDAY, June 12, 2026 (HealthDay News) — Postoperative delirium is associated with long-term cognitive decline, and the association is not mediated by rehospitalization, according to a study published online June 8 in JAMA Internal Medicine.

Tammy T. Hshieh, M.D., M.P.H., from Brigham and Women”s Hospital in Boston, and colleagues examined whether cognitive decline associated with postoperative delirium is mediated by illness and frailty in a prospective cohort study involving 560 community-dwelling older adults (age 70 years and older). The main outcome was long-term cognitive decline, measured as change in General Cognitive Performance (GCP) score, a composite measure of 11 neuropsychological tests.

The researchers observed an association for each rehospitalization with a decline of −0.19 GCP units per year. A more marked cognitive decline of −0.33 GCP units per year was seen in association with delirium. Among patients who developed delirium, rehospitalizations were more common (adjusted incidence rate ratio, 1.42). A minimal percentage change that was not statistically significant (−6 to −9 percent) was seen for the association of delirium with cognitive decline after adjustment for combined rehospitalizations and for each type of rehospitalization.

“We saw that delirium was associated with cognitive decline at a rate faster than what we would normally see with mild cognitive impairment and the effect was not mediated by rehospitalization,” Hshieh said in a statement. “This was surprising because we thought rehospitalization would explain at least some of the effect of delirium on long-term cognitive decline.”

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